Forecast Verification
How well did the forecasts do? This compares NBM and GFS highs and lows, as forecast 1, 3 and 5 days ahead, with what was actually observed at 16 major U.S. airports over the last 30 days, alongside CPC’s published skill scores for its own outlooks.
NBM vs GFS, last 30 days
Period: …. Error is the mean absolute error in °F; bias is forecast minus observed (positive means too warm).
| Station | NBM high error | NBM high bias | GFS high error | GFS high bias | NBM low error | NBM low bias | GFS low error | GFS low bias | Days |
|---|---|---|---|---|---|---|---|---|---|
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Forecasts: the runs issued 1, 3 and 5 days earlier, from Open-Meteo’s Previous Runs archive (NOAA NBM CONUS and GFS). Observations: station daily max/min from ACIS. The forecast high and low are the warmest and coolest hourly values in the local calendar day, while the observed values are true extremes. That can make forecast highs read slightly cool, so expect a small cold bias. The GFS shown is the global 0.25° run only. Its overnight lows tend to run several degrees warm, especially on clear, calm nights inland, because its grid is too coarse to resolve local cooling. That is a real model trait, not a data error. These are preliminary observations. Refreshed every 12 hours.
CPC outlook skill
CPC’s own Heidke skill scores for its latest verified monthly and seasonal outlooks. 0 means no better than chance and 100 is perfect.
| Outlook | Valid | Variable | HSS (non-EC) | HSS (all) | Non-EC coverage |
|---|---|---|---|---|---|
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Source: CPC verification. See the Climate page for the forecast and observed maps.